Ink spray printer

ABSTRACT

Printing on a document is done by moving a rotating shutter having a narrow slit, between the document and a rotating stencil having character apertures, and moving both past a print position in timed relation with an ink spray from a nozzle supplied with ink and air under pressure.

United 5 States Patent 191 Ku et a1. i

[111 3,865,031 [451 Feb. 11,1975

1 1 INK SPRAY PRINTER [75] Inventors: Ta-Cheng Ku, Endwell; Sherman H.

M. Tsao, Apalachin, both of N.Y.

[73] Assignee: International Business Machines Corporation, Armonk, N.Y.

22 Filed: Feb. 26, 1973 21 App1.No.:335,863

[52] US. Cl 101/114, 101/129, 197/48, 118/301, 117/38, 346/75 [51] Int.Cl. B411 13/00 [58] Field of Search 197/18, 48; 101/112, 114, 101/116,122, 127, 129, DIG. 13,48; 118/301; 346/75, 107 A, l R; 117/38 [56]References Cited UNITED STATES PATENTS 2,066,642 1/1937 Page 101/1142,532,802 12/1950 Farwell 101/112 X, 3,205,855 9/1965 Ault 118/301 XPlymale 101/129 X 3,307,477 3/1967 Boohcr 101/114 3,321,768 5/1967Byrd..... l0l/D1G. 13 3,363,552 'l/1968 Rarey 101/114 X 3,460,468 8/1969Johnson.... 10l/DlG, 13 3,599,225 8/1971 Babaoff 101/D1G. 13 3,617,33111/1971 lllslcy et a1 117/38 X 3,621,967 11/1971 Brown 101/114 X3,673,602 6/1972 Stefzmsson et a1. 346/107 A Primary Examiner-Edgar S.Burr Assistant Examiner-E. H. Eickholt Attorney, Agent, or FirmFrancisV. Giolma [57] ABSTRACT Printing on a document is done by moving arotating shutter having a narrow slit, between the document and arotating stencil having character apertures, and moving both past aprint position in timed relation with an ink spray from a nozzlesupplied with ink and air under pressure.

1 Claim, 12 Drawing Figures PATENTEDFEBI 1 1915 3,865,031

FIG.50

QFlG.4c FlG.5 c F lG.6c

1 INK SPRAY PRINTER BACKGROUND OF THE INVENTION 1. Field of theInvention The invention relates generally to printers and it hasreference in particular to ink jet printing using a character bearingstencil and a shutter through which the ink passes to form characters ona document.

2. Description of the Prior Art Ink jet printers are known such asdisclosed in US. Pat. No. 3,416,153, entitled Ink Jet Recorder, whichissued to C. H. Hertz et al. on Dec. 10, 1968, and it discloses anelectrode spaced from an ink nozzle for dispersing the spray andpreventing the spray from passing through a shield to impinge on adocument. U.S. Pat. No. 3,621,967, entitled Liquid Emission Typewriterissued to Irving I. Brown on Nov. 23, 1971 and discloses printing on adocument by means of an ink nozzle and a character bearing disc.

SUMMARY OF THE INVENTION Generally stated it is an object of theinvention to provide an improved ink jet printer.

More specifically it is an object of this invention to provide forinterposing a shutter between a character bearing mask or stencil and adocument upon which printing is to be performed by a spray of ink.

Another object of the invention is to provide for printing with acontrollable ink spray by utilizing a character bearing stencil and ashutter having a narrow slit moving past an ink nozzle at differentspeeds.

Yet another object of the invention is to provide for moving a shutterhaving a narrow slit, through the space between a character bearingstencil and a document upon which it is desired to print with a spray ofink under pressure from a nozzle.

It is also an object of the invention to provide for moving a shutterhaving a narrow slit, in a space between a document and a moving stencilcarrying character apertures with the stencil moving in the samedirection but faster than the shutter.

Another important object of the invention is to provide for printingwith an ink spray through a character bearing stencil moving past aprint position on a document, by having a shutter with a narrow slitmoving in the same direction but faster than the stencil.

It is also an important object of the invention to provide for printingby means of an ink spray through a moving character bearing stencil, byhaving a shutter with a narrow slit move between the stencil and adocument, but in the opposite direction.

One other object of the invention is to provide for printing on adocument by means of an ink spray by using a rotating stencil havingcharacter apertures and utilizing a rotating shutter positioned betweenthe stencil and the document having a narrow slit therein.

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of a preferred embodiment of the invention as illustrated inthe accompanying drawing.

DESCRIPTION OF THE DRAWING In the drawing FIG. 1 is a schematic partialview in vertical crosssection of printing apparatus using the inventionin one of its forms;

FIGS. 2 and 3 are enlarged partial views of the stencil and shutter ofFIG. 1 showing a typical character aperture and the slit,-respectively.

FIGS. 4a, 4b and 4c are enlarged partial views broken out in part of thestencil, shutter and document showing different steps in printing withthe stencil and shutter moving in the same direction, the stencil movingfaster than the shutter.

FIGS. 5a, 5b and 5c show similar views with the shutter moving fasterthan the stencil; and

FIGS. 6a, 6b and 60 show similar views with the stencil and the shuttermoving in opposite directions.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIG. I the referencenumeral [0 denotes generally a print head carrier mechanism utilizing anink jet nozzle structure 12 mounted on a carrier 14 for movement along aprint line on a document 16 positioned about a platen 18. Feed rolls 20and 22 are provided for feeding the document past the ink nozzlestructure 12. In order to provide for-printing characters on thedocument 16 a stencil 24 having a plurality of character aperturesadjacent the periphery, as represented by aperture 25 defining thecharacter x in FIG. 2 is moved past the ink jet nozzle structure. At thesame time a shutter 26 positioned between the stencil and the document16, is moved relative to the stencil 24 and is provided with a narrowslit 28 as shown in FIG. 3

scribed in either of the Hertz et al or Brown patents hereinbeforereferred to. It may also comprise an air brush type nozzle having an inknozzle 30 to which ink may be supplied through a conduit 32 inconjunction with air under pressure through a conduit 34. The air may becontrolled by means of a solenoid operated valve and an emitter (notshown) which is connected in driven relation with the stencil to providea spray of ink in timed relation with the passage of the characterapertures past the nozzle 30 in a manner well known in the art.

As shown in FIG. 1 the character bearing stencil 24 may comprise arelatively thin disc mounted on a hub 36 and supported on the carrier 14by means of a bearing 38. A bevel gear 40 is connected to the hub bymeans of a shaft 42 and is engaged by teeth 44 of a corresponding bevelgear mounted on a carrier drive shaft 46 so as to be slidable thereonbut keyed thereto by means of a key 48 to rotate with the carrier shaft.The carrier 14 is supported on the carrier shaft 46 and a parallel guideshaft 50 for motion along the print line.

The shutter 26 is likewise mounted on a hub 52 carried by a tubularshaft 54 concentric with the shaft 42 which passes therethrough. A gear56 is mounted on the other end of the shaft 54 for engagement with teeth58 of the gear mounted on the carrier shaft 46. Rotation of the carriershaft 46 rotates the gear teeth 58 and 44 driving the gears 56 and 40 inpredetermined relation so that the shutter 26 and stencil 24 rotate, forexample, in the same direction but at different speeds.

Referring to FIGS. 4a, 4b and 40 it will be seen that relative motionsof the stencil 24 and shutter 26 are such that when a given characteraperture 27 on the stencil 24, representing the letter F, in reverse,sweeps past a print position on the document, simultaneously the narrowslit 28 on the shutter 26 would also sweep past the same print positionbut at a different speed.

The nozzle structure 12 may be similar to that de- The result is thatthe shutter 26 continuously'exposes different portions of the characteraperture or cutout 27. If the ink spray is turned on just before thearrival of the character cutout 27 and the narrow slit 28 combination,the ink spray will sweep through different portions of the charactercutout 27 and print out in time the whole character F on the paper asshown by the shaded outline 29. In this particular example the stencil24 is moving faster than the shutter 26. A ratio of 2 to 1 in the speedsof the stencil and shutter has been found to be quite satisfactory.

Referring to FIGS. a, 5b and 50 a typical arrangement is shown for theshutter with a slit 28 and stencil with a character aperture 31representing the letter F, combination with the shutter 26 moving fasterthan the stencil 24. FIGS. 6a, 6b and 6c illustrate similarstages in theprinting of the character F with the stencil and shutter 24 having acharacter aperture 33 representing the character F travelling inopposite directions.

While the implementation of the invention has been shown in connectionwith rotating shutter and stencil constructions, the stencil and shuttermay be in the form of a tape, each driven at different speeds.Alternatively both the stencil and shutter may be of discs of eitherequal or different diameters and rotating at either different or thesame angular velocities. Both the shapes of the character cutouts on thestencil and the widths of the slits on the shutter should be designed inaccordance with the relative motions of the stencil, shutter and paperand the ink spray velocity. For example, in FIGS. 4a, 4b and 4c thewidth of the vertical legs of the character aperture 27 is on the orderof double the width of the desired character and the aperture 27 isreversed, left to right. The stencil 24 was rotated at rpm and theshutter 26 at 5 rpm. With reference to FIGS. 5a, 5b and 5c the width ofthe vertical section of the character aperture 31 in the stencil is onthe order of one-half the width of the actual character 29. In thisinstance the shutter was rotated at 20 rpm and the stencil at 10 rpm. Inthe illustration shown in.FlGS. 6a, 6b and 6c the width of the verticalleg of the character aperture 33 in the stencil 26 is on the order ofdouble the width of the desired printed character 29. The stencil 24 andshutter 26 travel in opposite directions the stencil and shutter bothoperating at about 10 rpm.

in one embodiment the shutter and stencil were approximately 4 inches indiameter and are made of a material non-wettable by the ink. Avinyl-like plastic such as Mylar or a stainless steel may be used. Thestencil 24 may be thick enough to be fairly rigid on the order of milswhile the shutter 26 may be relatively thin on the order of 3 to 5 milsthick and provided with a 6 to 10 mil wide slit. With the stencil24moving fasterthan moves faster than the stencil fewer slits may berequired, only half as many slits as characters being necessary when theshutter moves twice as fast as the stencil. Air at a pressure of 30 to50 lbs was used successfully with the ink itself being supplied at nearzero pressure. 7

For serial printer applications both the stencil and shutter may be inthe disc form, mounted on a moving carriage as shown. Printing may takeplace either at the 12 oclock positionor the 9 oclock position of therotating discs. Since the carriage is in continuous motion from left torightwhile printing the character cutouts in each case must bepositioned on the stencil disc so as to compensate for this motion. Inthe particular case where the printing takes place at the 9 oclockposition the character cutouts must be positioned along a helical spiralon the disc and in fact the character cutouts may be sped over a helicalspiral of several revolutions which together with a multiple printstation may result in an increase of the print rate without increasingthe speed of the printing operation itself.

While the invention has been shown and described with reference to apreferred embodiment thereof, it will be understood by those skilled inthe art that various changes in form and detail may be made thereinwithout departing from the-spirit and scope of the invention.

What is claimed is:

1. In character printing apparatus:

a nozzle having fluid ink supplied thereto under pressure to provide aspray of fluid ink directed at a document,

a stencil positioned between the nozzle and the document having aplurality of spaced apart character forming openings therein, saidstencil being movably mounted so as to continuously move said openingsbetween said nozzle and a position on said document where a character isto be printed,

a shutter movably positioned between said stencil and said document andhaving a narrow slit therein, said shutter being positioned tocontinuously move said slit between said nozzle and said print positionand relative to said character openings, and

drive means connected to said stencil and said shutter to move saidstencil past said print position in one direction and said shutter pastsaid print position in the opposite direction at different speeds.

1. In character printing apparatus: a nozzle having fluid ink suppliedthereto under pressure to provide a spray of fluid ink directed at adocument, a stencil positioned between the nozzle and the documenthaving a plurality of spaced apart character forming openings therein,said stencil being movably mounted so as to continuously move saidopenings between said nozzle and a position on said document where acharacter is to be printed, a shutter movably positioned between saidstencil and said document and having a narrow slit therein, said shutterbeing positioned to continuously move said slit between said nozzle andsaid print position and relative to said character openings, and drivemeans connected to said stencil and said shutter to move said stencilpast said print position in one direction and said shutter past saidprint position in the opposite direction at different speeds.